package com.yun.utils;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class DownloadPdf {

    /**
     * 从网络Url中下载文件
     * @param urlStr
     * @param fileName
     * @param savePath
     * @throws IOException
     */
    public static BufferedInputStream  downLoadByUrl(String urlStr,String fileName,String savePath) throws IOException{
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        //设置超时间为3秒
        conn.setConnectTimeout(5*1000);
        //防止屏蔽程序抓取而返回403错误
        conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");


        conn.setDoOutput(true); //需要输出 POST请求

        conn.setDoInput(true); //需要输入

        conn.setUseCaches(false); //不允许缓存

        conn.setRequestMethod("POST"); //设置POST方式连接//设置请求属性

        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        conn.setRequestProperty("Connection", "Keep-Alive");

        conn.setRequestProperty("Charset", "UTF-8");conn.connect();//建立输入流，向指向的URL传入参数 POST请求




        //得到输入流
        BufferedInputStream   inputStream =new BufferedInputStream(conn.getInputStream());
       /* //获取自己数组
        byte[] getData = readInputStream(inputStream);
        //文件保存位置
        File saveDir = new File(savePath);
        if(!saveDir.exists()){
            saveDir.mkdir();
        }
        File file = new File(saveDir+File.separator+fileName);
        FileOutputStream fos = new FileOutputStream(file);
        fos.write(getData);
        if(fos!=null){
            fos.close();
        }
        if(inputStream!=null){
            inputStream.close();
        }
        System.out.println("info:"+url+" download success");*/
        return inputStream;

    }


    /**
     * 从输入流中获取字节数组
     * @param inputStream
     * @return
     * @throws IOException
     */
    public static  byte[] readInputStream(InputStream inputStream) throws IOException {
        byte[] buffer = new byte[1024];
        int len = 0;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        while((len = inputStream.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        bos.close();
        return bos.toByteArray();
    }

    public static void main(String[] args) {
        try{
            downLoadByUrl("https://www.136.la/java/show-20182.html",
                    "ELISA3.pdf","c:/test");
        }catch (Exception e) {
            e.printStackTrace();
        }
    }

}
